Its eminent feature is its thousands of hoodoos and hoodoo rocks, referred to locally as "goblins",[4] which are formations of mushroom-shaped rock pinnacles, some as high as several meters. The distinct shape of these rocks comes from an erosion-resistant layer of rock atop softer sandstone.

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Evidence of Native American cultures, including the Fremont, Paiute, and Ute, is common throughout the San Rafael Swell in the form of pictograph and petroglyph panels. Goblin Valley is noted for several rock art panels as well as the rock formations. The secluded Goblin Valley was then found by cowboys searching for cattle. Then in the late 1920s, Arthur Chaffin, later owner/operator of the Hite Ferry, and two companions were searching for an alternate route between Green River and Caineville. They came to a vantage point about 1 mile (1.6 km) west of Goblin Valley and were awed by what they saw – five buttes and a valley of strange goblin-shaped rock formations surrounded by a wall of eroded cliffs. In 1949 Chaffin returned to the area he called 'Mushroom Valley'. He spent several days exploring the mysterious valley and photographing its scores of intricately eroded rocks.

Publicity attracted visitors to the valley despite its remoteness. In 1954 it was proposed that Goblin Valley be protected from vandalism. The state of Utah later acquired the property and established Goblin Valley State Reserve. It was officially designated a state park on August 24, 1964.

In October 2013 a delicately balanced hoodoo was intentionally knocked over by three Boy Scout leaders who had been camping in the area.[7] The men claimed that the hoodoo appeared ready to fall, and that they knocked it over to prevent park visitors from being hurt.[8] They recorded the illegal act and posted it to Facebook, but subsequently admitted that they should have told a park ranger. The hoodoo had existed for 20 million years, and had been formed out of rock that dated back as far as 165 million years.[4][8] Two of the men were subsequently dismissed from their leadership roles by the Utah chapter of the Boy Scouts, the Utah National Parks Council. The national Boy Scouts then removed them from Scouting altogether.[9] In January 2014, they were arraigned on felony charges of "intentionally damaging, defacing and destroying property".[10]

Vegetation is limited to hardy desert species that can endure blowing sand and hot dry surface conditions. Vegetation and wildlife exist on a limited supply of water in the arid desert environment. Plants have adapted by reducing the size of their leaves to reduce evaporation, with some having a waxy coating on their leaves that reduces water loss. Flora occupying Goblin Valley include Mormon tea (joint fir), Russian thistle, Indian ricegrass, and various cacti. Juniper and pinyon pine grow at slightly higher elevations.

Animals often must travel many miles to find water or else wait for thunderstorms to provide moisture. Most animals in the area are nocturnal, venturing out only in the cooler evenings to hunt and forage for food. Some animals get water from the food they eat and go for weeks without a drink of water. Jack rabbits, scorpions, kangaroo rats, pronghorn, kit foxes, midget faded rattlers, lizards, and coyotes are found within and near the park.

The unusual stone shapes in Goblin Valley result from the weathering of Entrada Sandstone. The Entrada consists of debris eroded from former highlands and redeposited on a former tidal flat of alternating layers of sandstone, siltstone and shale. The rocks show evidence of being near the margins of an ancient sea with the ebb and flow of tides, tidal channels that directed currents back to the sea and coastal sand dunes.

Joint or fracture patterns within the Entrada sandstone beds created initial zones of weakness. The unweathered joints intersected to form sharp edges and corners with greater surface-area-to-volume ratios than the faces. As a result, the edges weathered more quickly, producing the spherical-shaped 'goblins'.

The Entrada Sandstone from which the hoodoos developed was deposited in the Jurassic Period around 170 million years ago.[11]

Average daytime highs in the summer average between 90 °F (32 °C) and 105 °F (41 °C), though the low humidity, high elevation, and sparse vegetation allow evenings to cool off rapidly to about 50 °F (10 °C). Winters see colder temperatures and occasional snow, with temperatures above freezing most days but often dropping as low as 10 °F (−12 °C) at night. The average precipitation is less than 8 inches (20 cm). During the summer, the monsoon arriving from the south brings frequent intense and localized thunderstorms. The rugged terrain and intense rainfall can lead to devastating flash floods, while the low humidity combined with gusty winds and frequent lightning can spark wildfires.